1. Field of Invention
The invention relates to the structure of an ink jet recording apparatus of piezoelectric type and, more particularly, to the structure of an ink jet printer head including a sealing structure between a recording head and an ink path.
2. Description of Related Art
Conventionally, ink jet recording apparatuses are known which record on a recording medium, such as a sheet of paper, by ejecting droplets of ink thereon from the nozzles in a recording head based on input signals. In Japanese Laid-Open Patent Publication No. 8-276586, for example, the recessed part almost coinciding with the outer periphery of a recording head main body is formed to the rear surface of a head holder and connection ports are provided to the positions opposed to the ink supply ports. Edge parts protruding from the bottom surface of the recessed part are formed to the peripheries of the connection ports so as to become slightly outside from the inner peripheral surfaces of the ink passages. A space for absorbing an adhesive is formed to the inner periphery of each of the connection ports and a gap housing the adhesive is ensured on the other side.
In this case, the adhesive applied between the ink supply ports and the corresponding connection ports is poured into the ink supply ports, which interferes with ink supply. Therefore, in the known art, the outer periphery of each ink supply port is surrounded by the head holder, an edge part protrudes from the outer periphery of the ink supply port, and an adhesive is applied to the outer periphery of the edge part to fix the recording head.
As described above, once the adhesive is applied, it is difficult to replace the head holder and a circuit board with new ones.
The invention provides an ink jet printer head that prevents the occurrence of ink leakage and facilitates maintenance, such as part replacement.
In one aspect of the invention, an ink jet printer head includes a head holder that includes a supporting plate; a recording head that includes an array of nozzles on a bottom surface through which ink is ejected and an ink supply port on a top surface that supplies ink to the nozzles, the recording head fixed on the supporting plate; an ink path forming member that includes an ink path and an outlet and is fixed on a top surface of the supporting plate; a tubular sleeve that protrudes from the ink supply port of the recording head and is disposed so as to allow communication between the recording head and the outlet of the ink path; a backup plate that encloses a perimeter of the sleeve and is interposed between the recording head and the ink path forming member; an annular resilient sealing member that is inserted around the perimeter of the sleeve between the backup plate and the ink path forming member; and a fastener that fastens the backup plate to the ink path forming member. The annular resilient sealing member is resiliently deformed by the backup plate so as to prevent ink leakage from a connection between the perimeter of the sleeve and the outlet of the ink path.
Therefore, the outlet of the ink path in the ink path forming member on the head holder, which is fixed to the recording head, is not directly adhered to the sleeve, which is fixed to the recording head. The annular resilient sealing member inserted around the perimeter of the sleeve is pressed by the backup plate, so that a gap between the outlet and the sleeve is sealed. In addition, when the recording head or the ink path forming member is replaced, the sealed fit can be released by removing the backup plate only, and the parts are easily separable.